Some passenger and commercial vehicles use batteries to power electronic components. In hybrid vehicles, one or more batteries may be used to provide electrical energy to a motor that provides a torque that propels the vehicle. The operation of various control modules in the vehicle may depend upon the battery state of charge (e.g., the residual capacity of the battery relative to the reserve capacity). Further, a driver of the vehicle may wish to know how much longer the vehicle may be used before the battery must be recharged.